/usr/ is in libfastjson-dev 0.99.8-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/
/usr/include/libfastjson/
/usr/include/libfastjson/atomic.h
/usr/include/libfastjson/json.h
/usr/include/libfastjson/json_object.h
/usr/include/libfastjson/json_object_iterator.h
/usr/include/libfastjson/json_object_private.h
/usr/include/libfastjson/json_tokener.h
/usr/include/libfastjson/json_util.h
/usr/lib/
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/libfastjson.a
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/libfastjson.pc
/usr/share/
/usr/share/doc/
/usr/share/doc/libfastjson-dev/
/usr/share/doc/libfastjson-dev/copyright
/usr/lib/x86_64-linux-gnu/libfastjson.so
/usr/share/doc/libfastjson-dev/changelog.Debian.gz